Affiliation:
1. Corporate Research and Development, General Electric Company, Schenectady, NY 12301
2. General Electric Aircraft Engines, Evendale, OH 45215
Abstract
Aerodynamic flow path losses and turbine airfoil gas side heat transfer are strongly affected by the gas side surface finish. For high aero efficiencies and reduced cooling requirements, airfoil designs dictate extensive surface finishing processes to produce smooth surfaces and enhance engine performance. The achievement of these requirements incurs additional manufacturing finishing costs over less strict requirements. The present work quantifies the heat transfer (and aero) performance differences of three cast airfoils with varying degrees of surface finish treatment. An airfoil, that was grit blast and Codep coated, produced an average roughness of 2.33 μm, one that was grit blast, tumbled, and aluminide coated produced 1.03 μm roughness, and another that received further postcoating polishing produced 0.81 μm roughness. Local heat transfer coefficients were experimentally measured with a transient technique in a linear cascade with a wide range of flow Reynolds numbers covering typical engine conditions. The measured heat transfer coefficients were used with a rough surface Reynolds analogy to determine the local skin friction coefficients, from which the drag forces and aero efficiencies were calculated. Results show that tumbling and polishing reduce the average roughness and improve performance. The largest differences are observed from the tumbling process, with smaller improvements realized from polishing.
Reference27 articles.
1. Abuaf
N.
, BunkerR., and LeeP. C., 1997, “Heat Transfer and Film Cooling Effectiveness in a Linear Airfoil Cascade,” ASME JOURNAL OF TURBOMACHINERY, Vol. 119, pp. 302–309.
2. Bammert, K., and Sandstede, H., 1975, “Influences of Manufacturing Tolerances and Surface Roughness of Blades on the Performance of Turbines,” ASME Paper No. 75-GT-35.
3. Barlow
D. N.
, KimY. W., and FlorschuetzL. W., 1997, “Transient Liquid Crystal Technique for Convective Heat Transfer on Rough Surfaces,” ASME JOURNAL OF TURBOMACHINERY, Vol. 119, pp. 14–22.
4. Blair
M. F.
, 1994, “An Experimental Study of Heat Transfer in a Large-Scale Turbine Rotor Passage,” ASME JOURNAL OF TURBOMACHINERY, Vol. 116, pp. 1–13.
5. Bogard
D. G.
, SchmidtD. L., and TabbitaM., 1998, “Characterization and Laboratory Simulation of Turbine Airfoil Surface Roughness,” ASME JOURNAL OF TURBOMACHINERY, Vol. 120, pp. 337–342.
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